Recently, in the photographic art, light-sensitive silver halide photographic materials which are adaptable to rapid processing, which are capable of providing a high quality image and superior processing stability, and which can be manufactured at a lower cost have been in need. The particular need is for the material capable of ultra-rapid processing.
Usually, a light-sensitive silver halide photographic material is subjected to continuous treatment with an automatic developing machine installed in a development laboratory. To improve user-oriented service, same-day processing is required; the light-sensitive material is developed and returned to a user within the same day the material had been submitted to the laboratory. More recently, an even shorter processing service is required; the light-sensitive material is returned to a user within a few hours from the reception of the material. Thus, there are increasing needs for more rapid processing. At the same time, decreasing the processing time means improved processing productivity, and, possibly, lower costs. Therefore, rapid processing is an inevitable necessity.
Studies for achieving rapid processing have been centered on two aspects; the light-sensitive material and the processing solutions. In color developing, studies for achieving rapid processing have been based on higher temperature, higher pH level, higher concentration of color developing agents, and, further, additional additives such as development accelerators. Examples of such a development accelerator include 1-phenyl-3-pyrazolidones described in British Patent No. 811,185, N-methyl-p-aminophenols described in British Patent No. 2,417,514, and N,N,N',N'-tetramethyl-p-phenylenediamines described in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 15554/1975. However, these methods often fail to achieve sufficiently rapid processing and even incur deterioration such as increased fog.
Meanwhile, it is known that the configuration, size, and composition of silver halide grains in a silver halide emulsion greatly affect the developing speed and the like. It is also known that the halogen composition particularly affects the developing speed, and that an emulsion with high silver chloride content provides a remarkably high developing speed.
However, maintaining the rapid developability of a high chloride silver halide emulsion usually incurs increased fog.
Especially in the color developing system, because colored dye is formed, the fog density is more conspicuous than in that of a black and white developing system; this poses a serious problem in positively ensuring the rapid processability of high chloride silver halide emulsions.
Generally, antifogging agents are used to decrease the fog density. One of the most commonly known antifogging agents is potassium bromide which has been used in various developers. However, when a sample having high chloride silver halide emulsion is processed in a color developer system containing potassium bromide, its rapid processability is remarkably jeopardized. This means that potassium bromide acts as an extremely strong developing inhibitor o the high chloride silver halide emulsion rather than acting as an antifogging agent. Therefore, it is essential for rapid processing that potassium bromide is not virtually contained in the color developer system in which the high chloride silver halide emulsion is processed. Further, the fogging problem remains more difficult to solve.
Meanwhile, various other organic inhibitors are known as antifogging agents. For example, such agents are described in "Stabilization of Photographic Silver Halide Emulsions" by E.J. Birr, Focal Press (1974). Among these antifogging agents, many heterocyclic mercapto compounds have a strong antifogging effect and have been commonly used.
In general, light-sensitive silver halide photographic materials are uninterruptedly treated in various processing laboratories, with replenishers being continuously fed. It is impossible, in such an operation, to keep the compositions of processing solutions constant from the beginning through to the end of the running treatment. The resultant composition change of the processing solution causes a fluctuation in photographic properties. This problem is becoming more serious owing to the recent trend toward lower replenishing rates for processing solutions.
In regard to the composition change above, it is virtually impossible to completely avoid the developer becoming contaminated with the bleach-fixer, even by taking measures such as strictly predetermined replenishing rates for replenishers, evaporation prevention, and elimination of substances possibly eluted from the light-sensitive material. Therefore, especially in the case of a roller-conveyance type automatic developing machine, the degree to which the developer becomes contaminated with the bleach-fixer tends to fluctuate greatly depending on the amount of material being treated, and the squeezing manner. A lower replenishing rate of the processing solution causes greater contamination because the recycling rate of the processing solution decreases.
Furthermore, since the pH of the color developer is maintained at a high level, pH fluctuation of the color developer is unavoidable owing to the accumulated amount of the replenisher or air oxidation during the running treatment.
Such fluctuation in the color developer tends to induce fogging. Said antifogging agents can inhibit fogging to some extent if the agents are properly used.
However, an increase in minimum density (in magenta dye image, in particular) is induced during transition from the color developing process to the bleaching process in an automatic developing machine. Although this phenomenon can be prevented by using a considerable amount of said agents, a new problem occurs: developability and desilvering properties of the light-sensitive material deteriorate.